Unlike other types of transaction, you can reverse an allocation transaction. This creates a transaction of equal value, but with the opposite sign.
To reverse an allocation transaction:
If the number of allocation transaction lines exceeds a threshold number, the process will run asynchronously (in batch) and you will receive a notification when it completes. This threshold is controlled by a Document Line Volume custom setting. The type and destination of your notifications is controlled by an Accounting custom setting. Contact your administrator for more information.
If the number of allocation transaction lines is below this threshold, the process runs immediately.
The Apex job class for the Reverse Allocation Transaction process is ReverseTransactionBatch. See Allocation Transaction Log Fields and the Salesforce Help for more details on Apex jobs.